But it had a really thin OS layer, and everybody had virtually exactly the same box, so you could micro-optimize to the exact architecture. IMO it does fit the

But it had a really thin OS layer, and everybody had virtually exactly the same box, so you could micro-optimize to the exact architecture. IMO it does fit the concept of "domain specific stack", it's just that homogeneity is one of the important properties of the stack instead of unbridled performance.